The present invention relates generally to a Radio Frequency Identification (RFID) device having a nonvolatile ferroelectric memory, and more particularly to a RFID device having a nonvolatile ferroelectric memory for storing data processing states and values of a RFID tag when the power supply is interrupted.
Generally, a nonvolatile Ferroelectric Random Access Memory (FeRAM), which has about the same data processing speeds of a Dynamic Random Access Memory (DRAM), is spotlighted as possibly being a next generation memory device capable of conserving data even when the power is off.
FeRAM is structurally similar to DRAM in general, but FeRAM includes capacitors made of a ferroelectric substance having a high residual polarization, by which data retention is possible even after power is no longer provided to the FeRAM.
A RFID device includes a reader configured to automatically recognize an object equipped with an electric tag and to read information from it. RFID devices are widely used in inventory control, supply chain management, and factory automation due to their relatively rapid recognition performance speed and their large data storage capacity.
A RFID device includes a RFID reader and a RFID tag. The RFID reader includes an internal or external antenna. The antenna outputs an activating signal to radiate an electromagnetic field such as a RF field.
When a given RFID tag is exposed within a given RF field, the RFID tag receives the activating signal from the antenna of the RFID reader. By using the received activating signal to power up the RFID tag, the RFID tag can then subsequently transmit information stored in the RFID tag to the RFID reader.
That is, when the RFID tag is exposed within the RF field, an inducing voltage is generated in an antenna coil equipped in the RFID tag. The inducing voltage can then be rectified as a DC voltage and subsequently used as a power source required in a chip of the RFID tag. That is, the chip of the RFID tag is operated or activated when a given induced voltage is applied. Consequently, the data stored in a memory of the RFID tag can then be transmitted to a RFID reader.
When a number of different RFID tags is present within a reading range of the RFID reader, the RFID reader must be able to judge the data processing state of each RFID tag. A conventional RFID tag receives a RF signal to generate an induced power source therein. That induced power source is instantly disconnected depending on a state of the RF signal so that a current data processing state and value of the RFID tag can be eliminated. As a result, it is impossible to judge whether any one of the different RFID tags has already communicated with the RFID reader when exposed within the RF field emitted from the RF reader.
Furthermore, a conventional RFID tag must be re-initialized when the power source is re-supplied so as to re-process data in the RFID tag. Accordingly, the conventional RFID tag suffers delays in data processing speeds. Yet further, other data or information may have changed subsequent to being processed during a previous data processing event.